You can try this when he is on your shoulder. First, if you have long hair that he can climb on, pull it over with a clip to the opposite side. Also, be sure he has something on your shoulder to stand on that isn't slippery, like not direct on skin or slippery shirt - you can drape a t-shirt or towel on there.
Then using hand opposite side of shoulder, create a barrier between his and you. Your hand will be firm like a karate chop posture and you can talk to him and each time he tries to jump on on your hand, you can slide him over a bit away from your head. If he settles down let him know he's done well. After all this time with Pritti, sometimes he gets so excited and wants to climb all over me instead of perching on my shoulder or my lap or my chest if laying down, so i'll do the hand thing. He gets the point after a couple of minutes and calms down, then I make my hand into a snuggle ball shape and he cuddles up next to it, or in the crook of my neck.
As for the flying over -- can you intercept him with your arm or finger so that he lands on it. Like put it up in front of your head. Also I wonder if wearing a hat or cap or something would deter him for a while.
Lots of luck.